After years of plugging away as a singer and songwriter in Canada and Europe, what was the upside of your last album, TheReminder, selling a couple of million albums and winning four Grammy nominations?

I have a friend who says that anyone who complains about success deserves to be stripped of their talent. You just have to learn to adapt to going from years of nobody listening to everyone paying attention. So you have to not let that affect your own opinion of what you're doing. You can't look the gift horse in the mouth, but you can't let the horse run away with you, to beat the horse analogy to death.

So how did you feel about your track "1,2,3,4" suddenly taking off after the video appeared on an iPod ad?

I was naive and had no idea about the cult nature of Apple's appeal. It was just another decision I made that day – it seemed harmless and not a bad association to have. The truth is that no one was playing the video. And it was such a labour of love; it took three days. I would have said no if it was just the song, but I thought, "Great, someone will see the video."

How much was the video's elaborate, synchronised dancing influenced by your appearing in the opening ceremony of the Calgary Olympics as a child?

It wasn't deliberate, but it's uncanny how much the video has in common with that day. I was 12 years old at the time and we had rehearsed for two years. There were a thousand kids and we made shapes that you could see from above, like skiers and snowflakes. We started out in groups of 100 in the gym, then 200, then 300. By the end, we were rehearsing on football fields. Recently I got hold of a copy of the footage of the ceremony. It was over in three minutes. Two years for three minutes! But you try getting a thousand 12-year-olds to do something at the same time.

At the beginning of your new documentary, Look at What the LightDid Now, you seem thrilled to meet Kermit the Frog on the Grammy red carpet.

It's Kermit! My mom almost starts crying at that point because she knows I was basically raised by the Muppets. Meeting Kermit and Wilco was the worthwhile side of going to the Grammys. When I did "1,2,3,4" on Sesame Street they'd rewritten the song and made it about counting. At first, I balked. I was like, "Counting to four? That's where we're going with this?" Then they sent me appearances by other people like James Blunt doing "You're Beautiful" as "My Triangle".

The film is partly about everyone you work with. Were they protection against the sudden influx of attention?

I suppose having people I cared about around me meant there was something to hold on to, rather than me just flying into confusion. I mean, just the sheer amount of moving around you have to do, all the flights and early mornings – you start to lose your bearings. But there was no way I was going to complain. There's no crisis to solve in the film. I wanted it to be more subtle than that.

But there is a moment when you're unsure about whether you even want your face on your own album sleeve.

There's no mystery any more. So my instinct is to show very little, because there's much too much information about everyone, everywhere right now. Reality TV is an example of that.

You went to an alternative school in Canada. What was that like?

It was home to a lot of kids who thought it was the cool school, where lots of the interesting people I met at gigs went. You spoke to teachers on a first-name basis and you voted on everything that happened there, including course structure. It had a lot of kids who didn't gel with the high school system, which was where I started and had a lot of problems. Without even telling my mom, I transferred myself to the alternative school. I forged a letter and she found out a while later, but by that point I was settled in and not skipping classes anymore.

Didn't you go back there to give a talk?

I went back the year the Junos [Canada's Grammys] were in Calgary. When I was a student, once a month there would be guest speakers in the gym. People from places like the Canadian FBI, or activists, or the art teacher's son who had busked across Europe, just anyone. I phoned the school and said I'd like to come and do a Q&A. A lot of interesting people came out of that place. There's a guy who used to wear a skirt at school who's now a molecular biologist.

You lived in Berlin and Paris for a while...

I just wanted to move to places in Europe that I could feel poetic in! Musically, I didn't relate to Berlin. There seemed to be a lot of machine music made there – I don't think I saw a stringed instrument in two years. I didn't come to London as it's too expensive. It's true! I didn't really get London until I read Dickens. Then I was charmed to death by it.

You did get on French TV singing a duet with Juliette Gréco. How does one end up singing with a French icon?

I'm still not quite sure how it happened. And the language barrier meant that, initially, I wasn't aware of quite how much of a big deal she was. We stayed in touch for quite a while and she gave me some good advice like: don't let anyone tell you that you have to work at Christmas.